Multiple spot lamp



Sept. 27, 1932. c. F. JENKINS MULTIPLE SPOT LAMP Filed March 27, 1928 Patented Sept. 27, 1932 UNITED STATES PATENT OFFICE CHARLES FRANCIS JENKINS, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO JENKINS LABORATORIES, OF WASHINGTON, DISTRICT OF COLUMBIA, A CORPORA- TION OF THE DISTRICT OF COLUMBIA MULTIPLE SPOT LAMP Application filed March 27, 1928. Serial No. 265,032.

This invention relates to multiple spot glow lamps, preferably of the gaseous type employed principally in radio movies receiving apparatus. Heretofore lamps used in radio movies, radio vision, and television devices,

have been of a .single target type. The lamp is filled with gas, usually neon because of its availability and low voltage break-down point.

It is also customary to make the target a little larger than the picture to be reproduced. Thus, a received picture l-inch square requires a target about 1 inches square.

To illuminate a gaseous target 1% inches square in a lamp of this type, requires a large current, and therefore, enormous amplification from the extremely minute incoming radio current.

In applicants invention this lamp target area is divided up into very small targets, each of which is lighted in turn by a suitable switching gear.

To light these small targets requires a small current, a current easily within the amplification factor of usual radio receiving sets adequate for loudspeakers.

With these and other objects in view, the invention consists of the novel construction disclosed in the drawings herewith, its application in the mechanism employed, all as more particularly pointed out in the claims.

In the drawing, Figure 1 is a front elevation of a 3-target lamp; Figure 2 a side elevation of the same; and Figure 3 a switching gear for feeding current to the several targets in succession. Figure 4 is a front elevation of a G-target lamp; Figure 5 a side elevation; and Figure 6 a switching gear for distributing current to the targets in succession.

In all of the figures like symbols refer to like parts, in which A is a tube containing the targets and the enveloping gas;,B the press which seals in the supports 0, C, C", for the targets D, D, D; E is an anode serving all of the targets. D, 1D, 2D, 3D are wires which connect the segments of the switching gear 1F, 2F, 3F (Figure 3), each to its principal target. G is a switch arm carrying the contact blade H, and moving around the switch segments in the direction of the arrow; J is simply a glass button to support the anode accurately and uniformly spaced from the several targets. K is a wire leading to the switch contact G; L is a wire leading through the press from the anode E.

. In Figures 4, 5, and 6, the same schematic arrangement of lettering is carried out for G-targets as for the 3-target lamp and switch, of Figures 1, 2, and 3.

The lamp structure shown herein includes details of the structure of lamp shown in Pgatent No. 1,683,137, granted September 4, 1 2

The structure of the lamp which is of importance is that (1) the targets lie close to the glass wall; (2) that they be small requiring only little current to make them glow; and (3) that the light spot on each of these targets has a sharp, definite boundary between light and dark.

In the operation of this lamp current is applied to the two terminals L and K, with the result that the incoming current flows from K into G, thence by the blade H into the segment connected by wire 1D to wire M, and thence through support C to target D, thence through the gaseous atmosphere to anode E and wire L.

The movement of the switch blade H in the direction of the arrow puts each switch commutator segment and, therethrough, each of the targets, in succession into the electric circuit, with the result that each of the targets glow in succession, one at a time.

The result is great economy of current for a large area of picture.

And it is quite suflicient for the purpose, for, as is well known to those skilled in this art, only a single elementary area of the scanned picture surface is actually employed at any or e time, and there is, therefore, no 0ccasion to light a large picture area during the time it is unseen.

Locating the target close to the glass wall of the lamp permits bringing the glow spot close to any device which is used in the open air on the other side of the glass wall, reducing the light loss due to the inverse square law.

What I claim is- 1. In an electro-optical system the combination of an evacuated envelope having a. filling of conductive gas, a plurality of iscrete fiat plate targets, an anode common to i all said targets, and means including a source of image currents and a commutator for lighting each of said targets in succession over its entire area notwithstandin the variations in the image currents, t e luminous faces of said targets being dis osed within the envelope so as to be comp etely visible when energized.

2. A system according to claim 1 in which the cathode targets are mounted in close proximity to the wall of said envelope.

3. In an electro-optical system the combination of an evacuated envelope having a filling of inert conductive gas, a plurality of separate flat plate-like cathodes, a single anode common to all said cathodes each of said cathodes adapted to be illuminated over its entire surface when said anode is connected to a source of varying image currents said targets being disposcd within the envelope so that their entire luminoussurface is completely visible when energized.

4. In combination a gaseous lamp comprising an envelope having a quantity of conducting gas therein, said valve having a single press, a plurality of separate flat luminous cathode targets separated from said press with their luminous faces adjacent the envelope, a single anode common to all said cathodes, and a commutator for connecting each of said cathodes successively in circuit with said anode.

In testimony whereof I have afiixed my signature.

CHARLES FRANCIS JENKINS. 

